and Fruits, pt. 8: Simple Fleshy Fruits
A fruit is mainly an adaptation to effect seed dispersal and, as as such, is one of the few parts of a plant specifically "meant" to be eaten. Typically, portions of the ovary are nutritious, but the seeds, indigestible, pass though the fruit-eating animal unharmed (perhaps along with a little added fertilizer!).
Fleshy fruits are categorized based, in part, according to whether all of the fruit is fleshy, or instead there are bony or leathery parts. As such, a BERRY is the fleshiest of the fleshy, with the outer covering (exocarp), mid-section (mesocarp) and closely seed-surrounding center (endocarp) all being soft and digestible. Berries can be one-seeded or several-seeded. (Incidently, a lot of household fruits with "berry" as part of their name aren't actually berries. Strawberry? Not a berry. Blackberry? Nope. Raspberry? Uh-uh. Blueberry? Yes.)
Below, pokweed. This native wildflower, a favorite food of the now-extinct passenger pigeon, deserves a little more respect than it is usually afforded.
MOUSEOVER the image to see pokeweed in flower.
Wild senna fruits are legumes.
In a wildly successful, never-ending attempt to annoy our neighbors through botany, we are endeavoring to grow the biggest pokeweed plant in Columbus, in our front yard. It's shaped sort of like an elm tree.
Sequoia pokeweed in Columbus, Ohio, midsummer 2008.
Another very important, widepread fleshy fruit is the DRUPE.
"How are you?" "I'm peachy!" "Oh, I'm sorry to hear that." "Why are you sorry?" ""Because that must mean you are feeling kind of drupey" "Arghhh. That joke is really the endocarps"
A drupe, also known as a "stone fruit," is fleshy nearly throughout, except that it has a "pit," i.e., a thick bony endocarp surrounding a single seed in the center. Not only the peache, but also the cherry and plum are familiar drupes that happen to all be within the same genus, Prunus (family Rosaceae). Incidently, the almond "nut" (it isn't really a nut) is the stone of another Prunus. What you crack open with a nutcracker to expose the edible seed inside is the endocarp. The almond resembles a peach pit because it practically is one. The drupe is a common fruit type found in several plant families (often loosely called "berries.")
Below, black-haw. This is a common woodland shrub, a member of a family mainly consisting of opposite-leaved shrubs, the Caprifoliaceae, with three especially well-known genera: Viburnum (virburnums), Lonicera (honeysuckle), and Sambuscus (elderberry).
MOUSEOVER the image to see black haw in flower.
The viburnum fruit is a drupe.
The PEPO is a fruit type found in only one plant family, the gourd family (Cucurbitaceae). The pepo (gourd) is essentially a berry with a somewhat thickened rind (although there are other distintive gurd family traits too, such as having an inferior ovary and a peculiar way the seeds are attached inside the fruit, termed "parietal placentation"). Pumpkin, various squash, and cumcumber are household examples.
Below, wild cucumber. This is a native twining vine. Like all members of the Cucurbitaceae, it is monoecious, i.e., there are separate male and female flowers, produced on the same plant. Here (MOUSEOVER the image) the more abundant male flowers are in an upright cluster, while the less numerous female ones are positioned below them. While undergraduate students at SUNY ESF (Environmental Science and Forestry) in the 1970's, my friend Michael Corey and I got hired by a plant physiologist investigating plant hormones to gather big sacks full of wild cucumber fruits, pinch out their seeds, snip their ends, and carefully squeeze the juice (endosperm) into test tubes, over and over and over and over again. It was fun, actually.